POS0017 SEVERE GENERALIZED EDEMA AS INITIAL PRESENTING SYMPTOM IN POLYMYOSITIS
Authors: L. Francis, B. Mathew, R. Medina-Flores
Journal: Annals of the Rheumatic Diseases (2022)

Background 53 year old female developed pain and swelling of the metacarpophalangeal and proximal interphalangeal joints of both hands. She was diagnosed to have possible inflammatory arthropathy since her workup showed elevated inflammatory markers with CRP 2.2 and ESR 35. Rheumatoid factor and antiCCP antibody were negative. She was treated with hydroxychloroquine, methotrexate followed by leflunomide. She had non pitting edema around both ankles at initial presentation which later spread to the thighs, abdomen and chest. There was no erythema of the skin, tenderness or skin rash. BNP was normal at 58. TSH was normal. Echocardiogram was normal. Blood and urine cultures were negative. CT scan of the chest, abdomen and pelvis showed moderate subcutaneous edema. She was noted to have elevated liver enzymes with AST 438 and ALT 245. Hepatitis panel was negative. Smooth muscle antibody and antimitochondrial antibody were negative. Ultrasound abdomen showed diffusley increased echogenicity throughout the liver. Liver biopsy showed mildly active steatohepatitis centrizonal and portal/periportal fibrosis. ANA was positive 1:640 speckled pattern. ENA showed a positive antiRNP antibody. ANCA was negative. CK was elevated at 853 U/L. Myomarker panel was negative for antiJo, Anti Mi2, antiSRP, antiNXP and anti Ku antibodies. She had a workup for malignancy including CT chest, abdomen and pelvis, mammogram and colonoscopy which were negative. Objectives About 4 months after she presented with edema, she developed progressive proximal muscle weakness of both lower extremities which later involved both upper extremities. She also had neck muscle weakness. She also complained of difficulty swallowing. Swallow evaluation was normal. She did not have any skin rashes. Methods Concentric needle electromyography showed abnormal spontaneous activity; small amplitude and often polyphasic motor unit action potentials, along with increased recruitment pattern in tibialis anterior, vastus lateralis, medial gastrocnemius, tibialis posterior and short head biceps femoris muscle in the left lower extremity. The findings were suggestive of myopathy. She underwent a muscle biopsy from the left deltoid muscle which showed dense perimysial and endomysial lymphoplasmacytic inflammatory infiltrates with degenerating myofibers. Results Patient has proximal muscle weakness in both upper and lower extremities along with elevated CK, EMG findings suggestive of an underlying myopathy and biopsy evidence of inflammation and a diagnosis of polymyositis was made.She was initiated on treatment with a tapering course of prednisone starting at 60 mg daily. Her edema has improved. Liver function tests and CK have improved. Muscle strength has improved in both upper extremities with some residual weakness in the proximal muscles of lower extremities. Conclusion Patient presented with severe generalized edema as the initial presenting symptom of polymyositis. Rheumatologists should be aware of subcutaneous edema as a presenting manifestation of inflammatory myopathy and may precede the development of muscle weakness. Previously reported cases of edematous inflammatory myopathy were mostly dermatomyositis. This case demonstrates that polymyositis could also present as subcutaneous edema. References: [1] O Gorelik 1, D Almoznino-Sarafian, I Alon, M J Rapoport, G Goltsman, M Herbert, D Modai, N Cohen. Acute inflammatory myopathy with severe subcutaneous edema, a new variant? Report of two cases and review of the literature. Rheumatol Int (2001) 20: 163-166. [2] Chai Y, Bertorini TE, Li YD, Mitchell C, Guan H (2011). Limb edema and anasarca associated with severe dermatomyositis: report of four cases. Neuromuscul Disord 21:439–442. Disclosure of Interests None declared